Immobilized microorganisms exhibit the activity of the enzymes contained in the microorganism cells, and can often be used repeatedly over long periods of time. In some uses, these immobilized microorganisms are commercially advantageous over immobilized enzymes prepared by binding purified enzymes onto a resinous carrier.
Various methods have long been known for the production of immobilized microorganisms. In accordance with a typical method, the immobilization is performed by enclosing microorganism cells with gels, such as polyacrylamide gel, agar gel, carrageenan gel, collagen gel, calcium alginate gel, and polyvinyl alcohol gel (see I. Senhata, Ed., Immobilized Enzymes, Kodansha, Tokyo (1975)).
Immobilization of microorganism cells per se permits the omission of the step of extracting and purifying enzymes contained in the microorganism cells, because the enzyme can be used as it is as an enzymatic agent, and the yield of enzyme activity can be maintained at high levels.
Enclosing microorganism cells per se in polymeric gel, however, gives rise to the problems that the enzyme reactivity is reduced, and, when the degree of enclosing of the polymeric gel is lowered to increase the enzyme reactivity, the physical strength of the gel per se is deteriorated. It has therefore been desired to discover gels which can be commercially used over long periods of time.